#include<iostream>
using namespace std;
const int N = 1e5 + 10;
int arr[N];
int n, m;
bool check(double x)
{
	int ans = 0;
	for (int i = 1; i <= n; i++) {
		ans += arr[i] / x;
	}
	return ans >= m ? 1 : 0;
}
int main()
{
	cin >> n >> m;
	for (int i = 1; i <= n; i++)cin >> arr[i];
	double l = 0, r = 1e9;
	while (r - l > 1e-6) {
		double mid = (l + r) / 2;
		if (check(mid))l = mid;
		else r = mid;
	}
	printf("%.2lf\n", r);
	return 0;
}